A combat shotgun is a shotgun that is intended for use in an offensive role, typically by a military force. The earliest shotguns specifically designed for combat were the trench guns or trench shotguns issued in World War I. While limited in range, the multiple projectiles typically used in a shotgun shell provide increased hit probability unmatched by other small arms.

Most combat shotguns are fully automatic and have a drum magazine, giving them a definite advantage over break-action double-barrel shotguns.

The Heckler & Koch HK CAWS (H&K CAWS) is a prototype automatic shotgun—designed as a combat shotgun—co-produced by Heckler & Koch and Winchester/Olin during the 1980s. It was Heckler & Koch's entry in to the U.S military's Close Assault Weapon System program.

The Jackhammer, despite its name, is an easy to control shotgun, even when fired on full automatic. The popular bullpup design, which places the magazine behind the trigger, makes the weapon well balanced and easy to control.

The SPAS-12 was designed in the late 1970s by the Italian company Luigi Franchi Spa as a special purpose, military and police close combat weapon (SPAS originally stood for "Special Purpose Automatic Shotgun"; it was later renamed "Sporting Purpose Automatic Shotgun" in a failed bid to get import approval to the United States). This two-handed shotgun rapidly fires a thick, deadly blast of pellets.